


Superimposed

by Lunahras



Category: Undertale (Video Game)
Genre: Existential Crisis, Gen, Multiverse, Sans Has Issues, and tries to solve his problems by sleeping, basically this is what happens when i try to look for an in-multiverse explanation, but to conform to them, for why all the relevant interdimensional fancharacters are all sans, here you go have my shitty metaphysics, kinda meta but not really, mentions of several Aus up and including ink error dream nightmare and core frisk, playing around with sci fi quantum superposition i guess, theory, this is not meant to annull any other theory
Language: English
Status: Completed
Published: 2019-02-25
Updated: 2019-03-01
Packaged: 2019-11-05 06:11:42
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,866
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17913305
Author URL: https://archiveofourown.org/users/Lunahras/pseuds/Lunahras
Summary: "Tell me Sans,  all these influential, powerful, multiverse managing versions of yourself..."The bizarre buzzing laughter from before made a comeback, the unnerving sound echoing into infinity as the glowing eye curved upwards in sparking glee."Of all the people in the world, why do you think it's always you?"And Sans-Sans had no answer.





	1. Chapter 1

Sans woke up.

He panicked for a moment. Everything was dark. His eyes were open but everything was _dark he couldn't see he couldn't_ -

He could see his hands, his arms, his legs. He could see them perfectly well, even without a light source.

Sans looked up, around. Nope, no light to speak of, just a dark, empty void. An infinity of nothing. And yet here he stood, at the center of infinity, except infinity didn't have a center because everything was always right in the middle.

He halted that train of thought before it could get away from him. There were probably other things he should have been prioritizing, like the fact that he was here in the first place, whatever here was.

He looked at the darkness beneath his feet thoughtfully, then knelt and slid a slim finger bone along the surface he stood on. It had no texture to speak of, it didn't yield at pressure and yet it barely felt solid at all. Neither hard nor soft, it just was.

Where the  _hell_ was he?

** Nowhere in particular, really. **

He jumped and whirled around, feeling the familiar tug of magic in his left socket. He spun his head wildly. There was still nothing but him to occupy the void.

What...

** Oh, of course, silly me. I should give you something to look at. You work that way right now. **

He tensed and barely managed to suppress a flinch as a small line of golden light materialized a few feet in front of his face, splitting into two connected curved lines with a circle in the middle.

Sans blinked.

It was an eye, or at least a simplified, two-dimensional outline of an eye made out of faintly glowing golden lines, big enough to take up most of the space on an averagely sized face.

Well then.

Reluctantly, he let the magic in his eye fade away when it became clear that nothing but the floating eye doodle was about to materialize any time soon.

“...who are you?”

The eye narrowed and started shaking slightly with mirth, a strange buzzing sound reverberating through the darkness that – Sans vaguely came to realize – was probably some form of  _ laughter. _

** A predictable question, and yet one there is no real answer to. Or too many answers. Bringing certain concepts down to any measure of language and countability is rather difficult. **

The voice didn't come from the eye, but still from no direction particular, or maybe no direction at all. Sans' sockets narrowed just a tad, “try anyway.”

** Hmmmmmm. **

It sounded incredibly amused.

** Perhaps later. Wouldn't you rather know  _why_ you're here? **

“wherever _here_ even is...” Sans muttered in irritation. The eye seemed to swing whimsically from side to side.

** Semantics. What's important is you, and your role here. **

“...what role?”

** All of them really, so to say. But  _you_ specifically were chosen because of your circumstances. **

He frowned in both consternation and confusion. “my circumstances....? wait, chosen for what exactly?”

**Yes, you are a Sans from the original universe, you've experienced a relatively average life for being who you are, you've come into contact with your multiverse. They're not all necessary characteristics but they do make things easier.**

A cold sort of dread started building in his ribcage and he found himself almost stepping back from... whatever this thing was. Except that would be useless because this _being_ seemed to be absolutely everywhere, filling the void. Maybe it _was_ the void. Either way, the glowing outline was just a visual focus created to put him at ease. Stepping away from it would accomplish quite literally nothing.

Still, the instinct remained, a physical almost reaction reaching out from his spine to the tips of his limbs. This was-

This was too much. He had no idea where he was or what kind of omnipresent deity he was even talking to. He couldn't see anything at all beyond himself and the eye made of light that somehow reached no further than a few inches, not even the supposed floor on which he stood and didn't  _that_ give him vertigo. He couldn't hear anything except his own rasping breaths and the soft clacking of his bones against each other and that godforsaken humming, buzzing  _voice_ that surrounded him and smothered his senses like a suffocating pillow.

His foot moved back before he even registered it. It had too much momentum, made him lose his balance and start falling backwards. The thought of catching himself never even occurred to him.

There was no pain, but the ground was solid and not solid at the same time and managed either way to knock the breath out of him.

He stayed there on the floor for a while, saying nothing, barely daring to move. There was no pain but his chest felt increasingly colder and his head had formed a screaming harmony in three parts at some point in the last five minutes.

Five seconds.

Five hours.

He wasn't entirely sure.

** Are you just going to keep laying there? **

Sans swallowed dryly.

“dunno. are you going to take me back home?” he rasped out.

A scrambled huff vibrated through the nothingness.

** Do you have a home? **

And Sans... didn't really know what to say to that.

What was that supposed to mean? That he maybe didn't feel at home anywhere anymore? That the constant feeling of endless repetition that seemed to haunt his every step had made even his own home into a performative nightmare? That his universe had finally been destroyed for good and he'd somehow turned out to be the sole survivor because of  _ course he would- _

Deep breath. In. Out

No need to dwell on unknowns. Overthinking would just make things worse. He'd build himself into a panic and nobody wanted that.

“...do I?”

**Who knows.**

The voice passively this time, almost neutrally.

It was trying to trap him here and overwhelm him with unknowns.

Well then.

His breath calmed, his body relaxed and his lids drifted shut.

**Are you really going to take a nap here?**

Sans didn't react, just let himself drift off. Maybe he'd wake up at home.

Even with his eyes shut he had the feeling the eye looked rather unimpressed.

**Alright.**

…

…

…

Sans woke up.

The darkness went on and on and on. There was simply no end to it, it was headache inducing. But at least he couldn't see the non-existent ground when he was lying on it.

If he squinted enough he could almost tell himself there were stars dotting the inky blackness above him. Or around him, who even knew, his sense of direction was beyond screwed at this point.

**Morning sunshine.**

“there's no sun.” he spoke before he could stop himself and couldn't help but add, “if anyone here's sunshine it's you.”

**You say the sweetest things.**

Sans hummed but didn't answer. Or do anything at all. He just laid there and stared into nothing.

**That's going to get boring eventually.**

He curled up, his back directed pointedly at the weak golden light he could barely perceive on his peripherals.

Sleep embraced him like a loving mistress.

…

…

…

Sans woke up

There was ice in his chest, weighing it down. He felt exhausted.

He stared up.

The void stared back.

Neither of them blinked.

He heaved a sigh and sat up.

“alright, I'll bite.” he conceded as he stood “...why do you need a sans specifically?”

If the eye could've grinned, he was pretty sure it would have been widening beyond reason right now. As it was, it was making a disturbingly good attempt at mimicking the expression.

** Why would I need anyone  _else_ ? **

Sans frowned, eyelights snuffed out like candles. His ribcage felt colder, heavier. The eye watched him consideration and he could hear a vague humming undertone almost from inside his skull.

** So much worry, so unbalanced... **

It seemed to almost sigh. The sound was more felt than heard and it lingered in his teeth.

** Well, we work with what we have. So, you've met other versions of yourself, yes? **

Sans took a moment to collect himself, feeling vaguely insulted. He had no idea what this thing wanted from him but apparently the only way to make any sort of progress in here was going with its tangents. He'd play nice.

His sockets remained unlit.

“you're talking about alternate universes.”

** Your multiverse in itself yes, not just its universes and the timelines within them but also the spaces in-between. And its denizens, many of which are entities that make the whole of their multiverse theirs to influence. **

A frown. What was he getting at? Had those two chaotic gremlins fucked something up again?

“you mean like... ink? and error?”

** And Dream and Nightmare and so on. In some iterations of the multiverse even versions of you yourself, from the original universe, end up leading some form of universal coalition, or just managing aspects of their multiverse. **

His frown deepened as he kept his gaze on the glowing focus, “...you keep saying that.  _My_ multiverse,  _theirs_ . What's that supposed to mean? There's only that: the multiverse.”

Another echoing hum, almost like white noise in his bones.

** Not really. In the same way any one universe has an endless amount of timelines taking place simultaneously in the same space, the multiverse also has infinite iterations of itself, superimposed and overlapping. It works a bit differently on this large a scale and there's often some bleed-over between them, but it's a similar enough concept. **

This was

a bit

_ upsetting _ .

Having his worldview so thoroughly debunked once again hadn't been in his to-do list this year. It was, in fact, at the very bottom of his priorities. Bumping it up all of sudden was extremely rude.

He didn't want to continue this conversation.

“what... is that then? a double-multi-verse?”

His mouth apparently disagreed.

** You could call it infinity. Or reality. Does it really matter in the end? **

Sans could barely feel his arms going slack, his mind was abuzz.

Reality.

The fabric of reality itself.

The host of the shifting, superimposed multiverse.

_What kind of impossible scale was he even supposed to be thinking on?_

How was this utter mind-fuck even relevant??

“and... what does all that have to do with me?”

** Ah, finally at the crux of the matter. **

Oh yes, because  _that_ didn't sound ominous.

** Tell me Sans, all these influential, powerful, multiverse managing versions of yourself... **

The bizarre buzzing laughter from before made a comeback, the unnerving sound echoing into infinity as the glowing eye curved upwards in sparking glee.

**Of all the people in the world, why do you think it's always _you?_**

And Sans-

Sans had no answer.

It felt like his head was entirely blank, empty for once.

**Oh don't tell me you've never asked yourself that question? Sans the skeleton, simultaneously a normal monster and several god-like creatures alike. What is it, do you think, that makes you so special? Your unique power set? Your charming personality? Oh I know, I bet it's your mysterious past!**

This thing was-

It was-

There was a painful scraping sound as his fists tightened and his teeth gritted. This thing was mocking him, and rather deliberately at that. It was making this a game for itself, eye still bent in a mimicry of patronizing glee.

Of course he'd asked himself the question before, who wouldn't? It was one of the first solid thoughts he'd had after getting properly acquainted with the many entities that widely affected the multiverse. Even those like him, travelers and discoverers, tended to be versions of himself and his brother. Very rarely did he hear of someone else gallivanting between worlds, let alone meet them. He'd heard whispers of Core, barely rumours, but not much else. Everyone else remained, in some way, a Sans.

It was a question with no answer. There was no conceivable solution they could find. Not that they had much material to draw conclusions from in the first place. A few of them could remember things, their parent, their childhood, but for the rest of them...

There was nothing for him to extrapolate from, no past for him to remember.

**There is no past for you to remember because there is no past at all.**

Sans blinked, taken completely off-guard. _What?_

A buzzing chuckle sent a foreign shiver through his bones.

** That would be another reason why you were chosen, I guess. You're one of the original splits. **

_Splits?_

It was using too many new terms, too quickly. He was struggling to catch up.

**What does the name W. D. Gaster mean to you?**

The name sent him reeling for some unknown reason. He gave himself mental whiplash trying to wrap his head around the abrupt change of subject.

Sans' brow furrows in concentration, his previous irritation almost forgotten, “...nothing. should it mean something?”

**Not particularly, but it _is_ the key to your existence.**

It was said easily, almost like a remark of little importance, thrown in to fluff up the rest.

The eye spun once and swung from side to side. It was obviously trying to mess with him.

“explain.”

**Impatient, aren't we? Well, I guess I might as well start at the beginning.**

It paused, as if in thought.

**The _very_ beginning.**

He huffed in mild exasperation, “of the universe?” he joked tensely. Hands in his pockets to hide clenched fists and a grin sharp enough to cut through bone.

**Just about.**

“...oh...”

**Reality doesn't manage itself in its entirety. Or, well, it does, but not in an abstract sense. There always comes a time when its inhabitants start warping it, making little holes and cuts and glitches. For that, reality creates an Avatar. A representative, so to speak, to live amongst its population like any other creature. This Avatar then exists in every universe in some shape or form, without fail, and several iterations of it end up taking rather influential roles in shaping the multiverse. Gaster was one such Avatar.**

This... was a lot to take in. Um.

“and who exactly, uh... was he? as a person?”

**In the common populace, he was a skeleton monster, the royal scientist that came before Alphys, and the creator of the core.**

_Um. What._

There were no other skeleton monsters beside him and Papyrus. Not in his universe and certainly not in most others. They'd searched and yes, a few did house some, but...

“never heard of him.” he said with a frown.

**And neither has anyone else. W. D. Gaster goes forgotten, his existence has been almost completely erased.**

He almost gulped, “what... what happened to him?”

**He died. In an unfortunately permanent manner, at that.**

“ 'unfortunately permanent'?” he repeated with a raised eye-ridge, shoulders lowered but tense. The eye spun again, twice this time.

**Quite. Being what he was, his soul was considerably denser with information than any other being's. And his death, terrible as it was, was also repeated terribly often throughout universes in the same manner: He fell into the core, his body turned to dust, and his soul shattered and burst, dense as it was, scattering across space-time. An Avatar isn't meant to die, not permanently, or at least not entirely. But _his_ soul shattering, and it echoing through so many universes... it made a bit of a mess.**

He felt, for some reason, that he didn't want to hear the rest. The sensation felt not unlike looking into the endless void beneath his feet, an aimless sort of vertigo, a symptom of the terrifyingly unknown.

But he'd asked for answers, and he was being given _something_.

He forced himself to listen.

**The scattered pieces tried to coalesce, of course, and in some universes they succeeded, in others only partially. Instead, what tended to happen more often was that they ended up forming two whole new beings. Skeleton monsters, two sides of Gaster himself, holding different aspects of him...**

Slowly, he felt a sick, clammy tension filling his whole body, every space and every joint. He couldn'thave moved if he'd wanted to.

**And the status of Avatar passed onto one of them.**

Sans had gone entirely still, sockets darkened and startling horror etched across his face. The pool of dread in his chest had turned ice cold, freezing him from the inside out. His voice, when he forced it out, was raspy and bone dry (heh).

“....m-me?”

**You.**

The eye swayed and he could hear an indulgent smile in its voice. It oozed through him, between his bones, into his joints and the marrow of his bones, until he could not rid himself of the feeling.

Was this why...

**Why you have a certain awareness of other timelines in your universe? Indeed it is. It's yours to guard after all. You could technically have an awareness of the whole multiverse, of any other version of yourself, but as you are right now it'd be impossible. A creature as simple as a monster or a human couldn't possibly manage that kind of strain.**

Sans realized absently had it had been replying to his thoughts for a while now, but his mind could only majorly freak out over one huge mind-fuck at a time. It'd have to get in line with the rest of them.

A sudden, horrifying thought made his breath hitch. “but... what about papyrus? since he's also-”

**Yes, every now and then there's a universe in which it's Papyrus who takes on the role of Avatar, but it is always through your existence. His is tied to you and vice versa. Probably a side-effect of the whole soul-split situation.**

“why- why are you telling me this? do you tell every sans?”

**Goodness no, that'd be a recipe for disaster. They do their jobs well enough without this kind of awareness.**

The dread suddenly froze so cold that it burned. It burned and it blazed in his chest.

“then why me?” he demanded, trying to silence the raucous screaming in his head, like the screech of nails on ten chalkboards, “what do you want from me?!”

He found himself on his knees, with no memory of having lowered himself. His head spun. The edges of his vision went dark, darker. Icy panic gripped him. His ribcage expanded and shrank in quick succession for no practical reason. There's was an unhealthy whistle to his irregular breathing.

He looked at his hand, tried to focus on it. He saw the smooth, white bones, connected by magic. He saw the twitches of his fingers, the spasms of his wrist.

And then he didn't.

…

…

…

Sans woke up.

This time the eye hovered above him, looking dawn at his face.

He closed his eyes, opened them back up. It was still there.

He breathed, sat up, tried to shake off the cobwebs in his head. Took a moment or ten to recollect himself.

The eye waited. Or maybe the voice did. Or neither.

He prepared himself mentally-

And repeated the question in a raspy whisper.

“what do you want from me?”

**We need an Overseer.**

He blinked at the eye, “an... overseer?”

**A single iteration of you to act as a grand observer of reality. The Avatar's upper management, if you will. Even though there are still a few Gasters left throughout several universes, his overseer disappeared as soon as his role was passed onto you, so a new one is needed.**

He blinked again. It was saying words and stringing them in sentences but they still made no sense. Or barely any sense. The words were reorganizing themselves in his head. He was processing.

“why _now_?”

**The timing is irrelevant.**

His brow furrowed in annoyance. “irrelevant how?”

**The moment an overseer is created there will have always been one, in the same way you have always been an Avatar, even versions of you that weren't created by the split but in more natural ways or means completely unrelated to Gaster himself.**

That was... a rather complex concept, and not necessarily one he wanted to think too much about. He would give himself a permanent headache at this rate. He'd rather misdirect that train of thought before it really left the station.

“and what....exactly _is_ an overseer.”

**As an overseer you will cease being a monster, or any sort of mortal creature. Your shape may remain similar but your essence will be completely different. You will be a single entity, but you will also be every single iteration of yourself simultaneously.**

Sans cringed and frowned.

“that's, uh. that's a lot.”

**Yes.**

He looked into the eye, a doodle of light floating in the air in front of his face.

The eye looked back, somehow.

“what if I say no?”

**You would not be here if you were going to say no. You know what is at stake. Reality demands your existence and so you exist. You are its representative, these are your own wishes.**

Sans was quite for a while. A long while.

He sat down.

He breathed.

He thought.

His head was jumbled and he took his time trying to sort it out.

The voice didn't cut in, waiting patiently.

The eye was still, staring down at him.

He had all the time in the world.

He didn't know how long he sat there. There was no way of measuring time. No change in his environment or in himself. No thirst or gnawing hunger. No fatigue wearing him down.

Just him and his thoughts and a floating eye in the void of non-existence.

Overseer of the multiverse. Its greatest observer and influencer. The force to keep the balance of reality.

Sans the skeleton, omnipresent deity.

It was a daunting thought.

And yet.

Strangely.

_Interesting_ .

Finally, somewhere between minutes and decades later, he took a deep, entirely unnecessary breath.

“one last question.”

**Ask away.**

“who are you to be assigning such a role?”

A buzzing laugh once again, unnerving if not for the apathy that had settled into his bones like an old friend.

**I am temporary, a consciousness created for the sole purpose of explaining your role to you in a way that your mortal mind can understand. I exist to tell you things that you already know, but aren't consciously aware of in this form. I am a translator for infinity, and for you.**

“then you're... also a representative?”

The eye curved up with visible mirth.

**Of sorts, yes. In a way we are the same. Although I will cease to exist the moment you accept your role.**

Sans' eyelights shone with something almost approaching concern.

“and you're... okay with that?”

**I am not a full existence onto myself, and helping you along is my sole purpose for being. I do not mind finding an end soon since I see no reason for a continued existence. But thank you for your concern, I think you will be a good overseer.**

He let it go, chuckling, “You're so sure.”

**Of course.**

The ghost of a real smile.

“Of course.”

Another deep breath.

“Alright, I'll do it.”

The eye flashed once, twice. Then it disappeared.

**Awaken then, as a new being.**

The void faded. _Existence_ faded.

And then-

…

…

...

Sans woke up.

 


	2. illustration

**Summary for the Chapter:**

> Just adding a picture of seer/the overseer for visualization purposes ^^

**Author's Note:**

> i borrowed several concepts as well as the term avatar bc it is way too fitting not to use from Inyahs'fic Ava. it's amazing please go read it.
> 
> i guess i have a sans oc now. say hello to seer, short for overseer. he knows everything about every sans ever and probably has the best blackmail stockpile in the multiverse. i love him.


End file.
